LILO, which stands for "Linux Loader," is a boot loader used to load the Linux operating system. It allows users to select which operating system to boot when multiple systems are installed on a computer. LILO is particularly useful for managing dual-boot setups, where both Linux and another operating system, such as Windows, are present. LILO works by writing a boot record to the hard drive, which contains information about the installed operating systems. When the computer starts, LILO presents a menu for the user to choose from, making it easier to switch between different operating systems without complicated configurations.